This invention relates to a set of golf clubs, and, more particularly, to a set of golf clubs in which each club has substantially the same projected topline angle.
A conventional iron-type golf club includes a shaft and a clubhead. The clubhead includes a sole, a toe, a heel, and a topline. The loft of the club is defined by the angle between the plane of the face and a plane which extends through the centerline of the shaft and parallel to the leading edge of the clubhead. The topline angle is the angle between the top line of the clubhead and the ground plane which is tangent to the center of the sole. In most conventional sets of clubheads, the topline angle is substantially constant throughout the set.
When a golfer addresses a golf ball with an iron club, the topline of the clubhead and the leading edge of the clubhead define an angle which may be referred to as the projected topline angle, i.e., the angle which is projected onto the ground plane by the leading edge and the topline. The projected topline angle A is related to the topline angle B and the loft angle C by the expression: EQU A=arctan (tan B sin C)
For a typical set of irons, the angle A varies from club to club within a set. Thus, a golfer must deal with a different geometric picture for each club, and that may affect the golfer's ability to align the club properly. Even if a golfer is instructed to align the clubhead by positioning the leading edge of the clubhead perpendicularly to the intended line of flight of the ball, I believe that many golfers subconsciously also use the topline of the clubhead to align the clubhead. This theory is supported by data which indicates that many golfers tend to pull the short irons, i.e., the more lofted irons, and tend to push the long irons, i.e., the less lofted irons.
Many golfers feel most comfortable with a mid-iron, e.g., a 5 iron. I believe that when some golfers change to a lower number club, they open the club to obtain the same visual image as the 5 iron. The result is a push or a fade. When they use a higher number club, they close the club and produce a pull or a hook.